Electric vehicle power battery equalization system and method and electric vehicle

Abstract

The application provides a kind of electric vehicle power battery equalization system, method and electric vehicle, belong to electric vehicle power battery equalization control technical field, the equalization system, including: power battery pack, super capacitor group, equalization control unit and equalization control circuit;Each super capacitor in super capacitor group is connected in series, and each single battery in power battery pack is connected in parallel with corresponding super capacitor by equalization control circuit respectively;Equalization control unit is communicated with power battery pack, super capacitor group and equalization control circuit respectively;The equalization control unit is configured to receive each single battery remaining power and each super capacitor voltage detection value, and sends equalization control instruction to equalization circuit;The application realizes two-way complementary power transfer type non-dissipation equalization by the power of power battery pack and super capacitor group interaction.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric vehicle power battery equalization control, and particularly relates to an electric vehicle power battery equalization system, method and electric vehicle. BACKGROUND

[0002] The statements in this section merely provide background technology related to the present application and do not necessarily constitute the prior art.

[0003] The power battery pack is the main energy source of the electric vehicle, and the capacity and the residual capacity SOC (State Of Charge) of each battery in the battery pack are inconsistent. The inconsistency affects the maximum utilization of the effective capacity of the power battery pack, increases the safety risk of the power battery pack, accelerates the aging of the power battery pack, and reduces the service life of the power battery pack. In addition, the single batteries connected in series follow the Matthew effect. Since the load is consistent, the weakest single battery always bears the maximum pressure, and therefore the single battery ages faster in the entire power battery pack. Therefore, it is necessary to perform equalization control and management. Through the equalization control and management of the power battery pack, the overall capacity of the power battery pack can be improved, the safety of the power battery pack can be improved, and the service life of the power battery pack can be prolonged, so that the power battery pack ages uniformly, thereby improving the consistency of the aging degree SOH (State Of Health).

[0004] The inventor finds that the existing power battery equalization technology is mainly dissipative equalization, which has low efficiency, is prone to equalization deviation, has poor reliability, and has the risk of control system hardware failure due to passive dissipative equalization thermal fatigue. Some electric vehicles use a super capacitor group as an auxiliary power supply for vehicle starting and power supply during heavy load operation, and use a power battery pack for power supply during small load operation. However, the super capacitor group and the power battery pack each realize dissipative equalization, which not only has low equalization efficiency, but also wastes a lot of energy. SUMMARY

[0005] In order to solve the problems of the prior art, the present application provides an electric vehicle power battery equalization system, method and electric vehicle, which realizes bidirectional complementary energy transfer type non-dissipative equalization through the energy interaction between the power battery pack and the super capacitor group.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] In the first aspect, the present application provides an electric vehicle power battery equalization system.

[0008] The application discloses an electric vehicle power battery equalization system, which comprises a power battery pack, a super capacitor pack, an equalization control unit and an equalization control circuit.

[0009] Each super capacitor in the super capacitor pack is connected in series, and each single battery in the power battery pack is connected in parallel with a corresponding super capacitor through the equalization control circuit.

[0010] The equalization control unit is in communication with the power battery pack, the super capacitor pack and the equalization control circuit.

[0011] The equalization control unit is configured to receive the residual capacity of each single battery and the voltage detection value of each super capacitor, and send an equalization control instruction to the equalization circuit.

[0012] As an optional implementation manner, the charging redundancy of the super capacitor is greater than or equal to the maximum equalization amount of each single battery.

[0013] As an optional implementation manner, the equalization control instruction is a one-way or two-way equalization control instruction, wherein the one-way equalization control instruction refers to the equalization from the power battery to the super capacitor pack, and the two-way equalization control instruction refers to the equalization from the super capacitor pack to the power battery pack first, and then the equalization from the power battery pack to the super capacitor pack.

[0014] In a second aspect, the application provides an electric vehicle power battery equalization method.

[0015] The electric vehicle power battery equalization method is used for charging the power battery pack by using the electric vehicle power battery equalization system in the first aspect of the application, and comprises the following processes.

[0016] If the charging cut-off condition is met, the charging is stopped; otherwise, the following processes are performed.

[0017] The residual capacity of each single battery in the power battery pack is obtained.

[0018] The capacity of each single battery greater than the minimum residual capacity is transferred to the corresponding super capacitor.

[0019] When the residual capacity of each single battery is equal to the minimum residual capacity, or the difference between the residual capacity of each single battery and the minimum residual capacity is within a preset range, the equalization is stopped, the charging of each single battery is started, and the above processes are circularly performed until the charging of the power battery pack is completed.

[0020] After the charging of the power battery pack is completed, each super capacitor in the super capacitor pack is charged according to the design redundancy until the charging is completed.

[0021] As an optional implementation, the charge cut-off condition comprises at least: reaching the highest charging voltage of the single battery, reaching the longest charging time of the single battery, or reaching the highest surface charging temperature of the single battery.

[0022] As an optional implementation, the voltage detection values of the super capacitors in the super capacitor group are obtained, and when the residual capacity of at least one super capacitor in the super capacitor group is less than the equalization amount required by the corresponding single battery, the reverse equalization is performed on each super capacitor in the super capacitor group to the corresponding single battery.

[0023] As an optional implementation, the reverse equalization comprises:

[0024] transferring the electric quantity of each super capacitor greater than the minimum residual electric quantity of the super capacitor to the corresponding single battery;

[0025] stopping the equalization of the super capacitor group when the residual electric quantity of each super capacitor is equal to the minimum residual electric quantity of the super capacitor, or the difference between the residual electric quantity of each super capacitor and the minimum residual electric quantity of the super capacitor is within a preset range;

[0026] continuing the charging process of the power battery group.

[0027] In a third aspect, the present application provides a power battery equalization method for an electric vehicle.

[0028] A power battery equalization method for an electric vehicle, which utilizes the power battery equalization system for an electric vehicle of the first aspect to charge the power battery group, comprising the following processes:

[0029] when the SOC is greater than a set value, the BMS has no discharge circuit cut-off fault, the minimum single battery voltage is greater than a set value, the voltage difference of each single battery is greater than a set value, the difference between the SOC of the battery group and the SOC of the super capacitor group is greater than a set value, and there is no voltage acquisition fault;

[0030] calculating the average voltage of all single batteries, transferring the electric quantity of the highest N single batteries greater than the average voltage of the single batteries to the single battery with the lowest voltage, until the voltage of the single battery is greater than the average single battery voltage of the super capacitor group.

[0031] In a fourth aspect, the present application provides a power battery equalization method for an electric vehicle.

[0032] A power battery equalization method for an electric vehicle, which utilizes the power battery equalization system for an electric vehicle of the first aspect to discharge the power battery group, comprising the following processes:

[0033] obtaining the residual electric quantity of each single battery in the power battery group;

[0034] When the difference between the maximum remaining power and the minimum remaining power in each single battery is greater than a set value, discharging equalization is performed until discharging cutoff;

[0035] The discharging equalization comprises: transferring the power of each single battery greater than the minimum remaining power to the corresponding super capacitor.

[0036] As an optional implementation, the voltage detection values of each super capacitor in the super capacitor group are acquired, and when the remaining capacity of at least one super capacitor in the super capacitor group is less than the equalization amount required by the corresponding single battery, reverse equalization is performed from each super capacitor in the super capacitor group to the corresponding single battery.

[0037] As an optional implementation, the reverse equalization comprises:

[0038] transferring the power of each super capacitor greater than the minimum remaining power of the super capacitor to the corresponding single battery;

[0039] When the remaining power of each super capacitor is equal to the minimum remaining power of the super capacitor, or the difference between the remaining power of each super capacitor and the minimum remaining power of the super capacitor is within a preset range, the equalization of the super capacitor group is stopped.

[0040] The discharging process of the power battery group is continued.

[0041] In a fifth aspect, the present application provides a power battery equalization method for an electric vehicle.

[0042] A power battery equalization method for an electric vehicle, which utilizes the power battery equalization system for an electric vehicle of the first aspect to charge the power battery group, comprising the following processes:

[0043] When the SOC is less than a set value, the BMS has no discharging loop cut-off fault, the maximum voltage of the battery single is less than a set value, the voltage difference of each battery single is greater than a set value, the difference between the SOC of the battery group and the SOC of the super capacitor group is greater than a set value, and there is no voltage acquisition fault;

[0044] The average voltage of all single batteries is calculated, and the power of the highest N battery singles greater than the average voltage of the single battery is transferred to the single capacitor with the lowest voltage until the voltage of the single capacitor is greater than the average single capacitor voltage of the super capacitor group.

[0045] In a sixth aspect, the present application provides a power battery equalization method for an electric vehicle.

[0046] A power battery equalization method for an electric vehicle, which utilizes the power battery equalization system for an electric vehicle of the first aspect to charge the power battery group, comprising the following processes:

[0047] After the BMS hibernation setting time, when the SOC is greater than the set value, the maximum battery cell voltage is less than the set value, the pressure difference of each single battery is greater than a certain value, the difference between the super capacitor group SOC and the battery group SOC is greater than the set value, there is no voltage acquisition fault, and the BMS power supply voltage is greater than the set value;

[0048] Calculate the average voltage of all single cells, and transfer the power of the highest N battery cells greater than the average voltage of the single cells to the single capacitor with the lowest voltage until the voltage of the single capacitor is greater than the average single capacitor voltage of the super capacitor group.

[0049] In a seventh aspect, the application provides an electric vehicle.

[0050] An electric vehicle comprises the electric vehicle power battery equalization system of the first aspect of the application, and the power battery group and the super capacitor group are directly or indirectly connected with the motor drive control system of the electric vehicle.

[0051] In an eighth aspect, the application provides an electric vehicle.

[0052] An electric vehicle uses the electric vehicle power battery equalization method of the second aspect, the third aspect, the fourth aspect, the fifth aspect or the sixth aspect of the application.

[0053] Compared with the prior art, the application has the following beneficial effects:

[0054] 1. The application innovatively provides an electric vehicle power battery equalization system, method and electric vehicle, which realizes bidirectional complementary power transfer type non-dissipative equalization through the power transfer between the power battery group and the super capacitor group.

[0055] 2. The application innovatively provides an electric vehicle power battery equalization system, method and electric vehicle, which transfers the residual power greater than the minimum residual power SOC or the average residual current in all single cells to the super capacitor, selectively equalizes and transfers through the equalization control unit, and can also perform reverse equalization on each super capacitor of the super capacitor group.

[0056] 3. The application innovatively provides an electric vehicle power battery equalization system, method and electric vehicle, which combines the power battery group and the super capacitor group as the energy source of the electric vehicle, forms an energy storage system with high energy density and high power density output, uses the high power density characteristics of the super capacitor group to supply power (strong power system) to the electric vehicle when the electric vehicle starts or runs under heavy load, and uses the high energy density characteristics of the power battery group to supply power (strong power and weak power system) to the electric vehicle when the electric vehicle runs under medium or small load, so that the cruising range of the electric vehicle can be greatly improved, the large current output of the power battery group can be avoided, the use performance of the power battery group can be improved, and the service life of the power battery group can be prolonged.

[0057] 4. The application provides the electric vehicle power battery equalization system, method and electric vehicle, and the rapidity of super capacitor group charging can improve the equalization efficiency, and the non-dissipative charge transfer equalization scheme can avoid the difficulty of non-adjacent single battery equalization in the previous equalization scheme.

[0058] 5. The application provides the electric vehicle power battery equalization system, method and electric vehicle, and the unbalanced electric quantity is directly transferred from the power battery group to the super capacitor group, avoiding the defect that the unbalanced electric quantity is transferred in the power battery group in the previous equalization scheme; and the transferred electric quantity can be used as a supplement of the super capacitor group under the condition that the super capacitor group cannot be charged.

[0059] The advantages of the additional aspects of the application will be partially given in the following description, partially become obvious from the following description, or be known by the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0060] The drawings accompanying the specification of the application form a part of the specification and serve to further illustrate the application, the illustrative embodiments of the application and the description thereof serve to explain the application without imposing undue limitation on the application.

[0061] Figure 1 The structural schematic diagram of the electric vehicle power battery equalization system provided for the embodiment 1 of the application.

[0062] Figure 2 The power battery group equalization circuit schematic diagram provided for the embodiment 1 of the application.

[0063] Figure 3 The flow schematic diagram of the electric vehicle power battery equalization method provided for the embodiment 2 of the application.

[0064] Figure 4 The power battery group equalization circuit schematic diagram provided for the embodiment 2 or the embodiment 3 of the application Figure 1 .

[0065] Figure 5 The power battery group equalization circuit schematic diagram provided for the embodiment 2 or the embodiment 3 of the application Figure 2 .

[0066] Figure 6 The flow schematic diagram of the electric vehicle power battery equalization method provided for the embodiment 3 of the application.

[0067] Figure 7 The power battery group equalization circuit schematic diagram provided for the embodiment 4 of the application. DETAILED DESCRIPTION

[0068] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0069] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0070] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0071] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0072] Example 1:

[0073] like Figure 1 As shown, Embodiment 1 of the present invention provides an electric vehicle power battery balancing system, including: a power battery pack, a supercapacitor pack, a balancing control unit, and a balancing control circuit;

[0074] The supercapacitors in the supercapacitor pack are connected in series, and each individual cell in the power battery pack is connected in parallel with the corresponding supercapacitor through a common equalization control circuit.

[0075] The equalization control unit communicates with the power battery pack, the supercapacitor pack, and the equalization control circuit, respectively.

[0076] The equalization control unit is configured to receive the remaining power of each individual battery cell and the voltage detection values ​​of each supercapacitor, and send equalization control commands to the equalization circuit; more specifically, the equalization control unit can receive the remaining power SOC of each individual battery cell, the voltage detection values ​​of each supercapacitor, and the charging cut-off and discharging cut-off signals of the power battery pack in real time.

[0077] In this embodiment, the unidirectional equalization control command refers to simply equalizing the power battery to the supercapacitor bank; the bidirectional equalization control command refers to first equalizing the supercapacitor bank to the power battery bank, and then equalizing the power battery bank to the supercapacitor bank.

[0078] In this embodiment, the supercapacitors in the supercapacitor bank, which serves as an auxiliary power source, are designed with charging redundancy based on the maximum equalization capacity of individual cells to prevent the lack of equalization capacity to balance the individual cell bank during discharge.

[0079] In this embodiment, each super capacitor is connected in series to form a super capacitor group, and each single battery is connected in parallel with a super capacitor through a common equalization circuit, i.e., the single battery and the super capacitor are strictly in a one-to-one relationship. The working voltage of the super capacitor group is between 1V and 3V (preferably 2V in this embodiment), and according to the total voltage requirement, a plurality of super capacitors need to be connected in series, so the number of super capacitors can be more than the number of single batteries.

[0080] Specifically, taking a low-speed electric vehicle as an example, when the total voltage requirement is 48V, at least 24 super capacitors of 2V need to be connected in series. At this time, if the ternary lithium battery single body (nominal voltage of 3.7V) is still used, at least 13 ternary lithium battery single bodies need to be connected in series, and each single body is connected in parallel with a corresponding super capacitor through an equalization circuit, as shown in FIG. 1. Figure 2

[0081] Taking the ternary lithium battery single body as an example, it is assumed that the voltages of the battery single bodies E1-E13 are 3.5V, 3.5V, 3.6V, 3.7V, 3.5V, 3.4V, 3.5V, 3.5V, 3.6V, 3.7V, 3.5V, 3.4V and 3.4V, respectively, the maximum equalization amount of each battery single body is 0.5V, and the voltage of each super capacitor in the super capacitor group is 2V; the maximum limit of charging of each super capacitor C1-C13 is 1.5V, and 0.5V is left as a redundant equalization capacity of the power battery single body.

[0082] In the equalization circuit, the connection between the battery single body and the super capacitor can be realized by adding a control switch in the line between them.

[0083] It can be understood that in other embodiments, one single battery can also correspond to at least two super capacitors, for example, each single battery can be connected in parallel with two adjacent super capacitors in series, and the equalization of one battery single body can be realized through two super capacitors; in some other embodiments, each battery single body can also be connected with all super capacitors through a switch circuit module, realizing the equalization connection between the single battery and any super capacitor.

[0084] It can be understood that in other embodiments, one super capacitor can also correspond to at least two single batteries, for example, each super capacitor can be connected in parallel with two adjacent single batteries in series, and the equalization of two single batteries can be realized through one super capacitor; in some other embodiments, each super capacitor can also be connected with all single batteries through a switch circuit module, realizing the equalization connection between the super capacitor and any single battery.

[0085] Embodiment 2:​

[0086] As Figure 3 shown, the embodiment 2 of the present application provides a method for balancing power battery of electric vehicle, using the power battery balancing system of the embodiment 1 of the present application to charge the power battery pack, including the following processes:

[0087] If the charging cut-off condition is met, stop charging; otherwise, execute the following processes:

[0088] Obtain the residual capacity of each single battery in the power battery pack;

[0089] Transfer the capacity of each single battery greater than the minimum residual capacity to the corresponding super capacitor;

[0090] When the residual capacity of each single battery is equal to the minimum residual capacity, or the difference between the residual capacity of each single battery and the minimum residual capacity is within the preset range, stop balancing, start charging each single battery, and cycle the above processes until the power battery pack is fully charged;

[0091] After the power battery pack is fully charged, charge each super capacitor of the super capacitor pack according to the design redundancy until completion.

[0092] In this embodiment, the charging cut-off condition includes at least: reaching the highest charging voltage of the single battery, reaching the longest charging time of the single battery, or reaching the highest surface charging temperature of the single battery. It can be understood that in other embodiments, the charging cut-off condition can be any factor that is not conducive to charging safety, such as charging speed exceeding a preset threshold, charging environment temperature exceeding a preset threshold, etc. Those skilled in the art can select according to specific working conditions, which will not be described here.

[0093] For example, one-to-one parallel connection of the battery monomers and super capacitors in Figure 2 , the voltages of the battery monomers E1-E13 are 3.5V, 3.5V, 3.6V, 3.7V, 3.5V, 3.4V, 3.5V, 3.5V, 3.6V, 3.7V, 3.5V, 3.4V and 3.4V, respectively. The minimum residual capacity of the battery monomers is 3.4V, and the to-be-balanced amount of each battery monomer is 0.1V, 0.1V, 0.2V, 0.3V, 0.1V, 0V, 0.1V, 0.1V, 0.2V, 0.3V, 0.2V, 0V and 0V, respectively. The to-be-balanced amount is transferred to the corresponding super capacitor.

[0094] Optionally, in some other embodiments, the equalization control unit acquires the voltage detection values of each super capacitor in the super capacitor group, and performs reverse equalization on each super capacitor in the super capacitor group to the corresponding battery cell when the residual capacity of at least one super capacitor in the super capacitor group is less than the equalization amount required by the corresponding battery cell. Specifically, for example, when the current voltage of C4 is 1.8V, the equalization amount of battery cell E4 is 0.3V, which exceeds the equalization capacity of C4 (assuming that the maximum voltage of C4 is 2V), at this time, reverse equalization can be performed first, that is, the electric quantity in the super capacitor is equalized to the battery cell.

[0095] Specifically, reverse equalization can be:

[0096] transferring the electric quantity of each super capacitor greater than the minimum residual electric quantity of the super capacitor to the corresponding battery cell;

[0097] stopping the equalization of the super capacitor group when the residual electric quantity of each super capacitor is equal to the minimum residual electric quantity of the super capacitor, or the difference between the residual electric quantity of each super capacitor and the minimum residual electric quantity of the super capacitor is within a preset range;

[0098] continuing the charging process of the power battery group.

[0099] For example, the voltages of C1-C13 are 1.3V, 1.4V, 1.4V, 1.8V, 1.3V, 1.4V, 1.5V, 1.5V, 1.4V, 1.5V, 1.5V, 1.4V and 1.4V, respectively, and the equalization amounts of C1-C13 are 0V, 0.1V, 0.1V, 0.5V, 0V, 0.1V, 0.2V, 0.2V, 0.1V, 0.2V, 0.2V, 0.1V and 0.1V, respectively, and the voltages of each battery cell E1-E13 after equalization are 3.5V, 3.6V, 3.7V, 4.2V, 3.5V, 3.5V, 3.7V, 3.7V, 3.7V, 3.9V, 3.7V, 3.5V and 3.5V, respectively.

[0100] The equalization of the power battery group is performed again, at this time, the voltages of C1-C13 are all 1.3V, and the equalizable capacity is 0.7V, and the equalization amounts of each battery cell C1-C13 are 0V, 0.1V, 0.2V, 0.7V, 0V, 0V, 0.2V, 0.2V, 0.2V, 0.4V, 0.2V, 0V and 0V.

[0101] Understandably, in some other implementations, the reverse balancing can also be done in other ways. For example, instead of using the minimum remaining capacity of the supercapacitor as the standard, a set balancing benchmark can be used. With a certain value as the benchmark (this benchmark is less than the minimum remaining capacity of the supercapacitor), all the remaining capacity of each supercapacitor that is greater than this benchmark is transferred to the corresponding battery cell. When the remaining capacity of each supercapacitor is equal to the minimum remaining capacity of the supercapacitor, or when the difference between the remaining capacity of each supercapacitor and the minimum remaining capacity of the supercapacitor is within a preset range, the balancing of the supercapacitor group is stopped, and the charging process of the power battery pack continues.

[0102] Understandably, in some other implementations, the balancing of each supercapacitor within the supercapacitor bank can be performed before or after reverse balancing to ensure that there is always a certain margin to achieve balancing of each individual cell. In other implementations, each supercapacitor can be connected to certain dissipation components to ensure that the supercapacitor can effectively release a certain amount of capacity to achieve balancing of each cell. Those skilled in the art can choose according to the specific operating conditions, which will not be elaborated here.

[0103] like Figure 4 As shown, it is also possible for one battery cell to correspond to two supercapacitors connected in series. Battery cell E1 is connected in parallel with supercapacitors C1 and C2 connected in series; battery cell E2 is connected in parallel with supercapacitors C3 and C4 connected in series; battery cell E3 is connected in parallel with supercapacitors C5 and C6 connected in series; battery cell E4 is connected in parallel with supercapacitors C7 and C8 connected in series; battery cell E5 is connected in parallel with supercapacitors C9 and C10 connected in series; battery cell E6 is connected in parallel with supercapacitors C11 and C12 connected in series; and battery cell E7 is connected in parallel with supercapacitors C13 and C14 connected in series.

[0104] The to-be-balanced amount of each battery cell can be equally divided into two series supercapacitors, for example, the balanced amount of battery cell E1 is 0.1V, then supercapacitor C1 and supercapacitor C2 each receive 0.5V of electricity; it can be understood that in other embodiments, 0.1V can also be proportionally allocated according to the remaining capacity of supercapacitor C1 and supercapacitor C2, for example, the current voltage of supercapacitor C1 is 1.3V (when the upper limit of capacity is 2V, the remaining capacity is 0.7V), the current voltage of supercapacitor C2 is 1.4V (when the upper limit of capacity is 2V, the remaining capacity is 0.6V), and the remaining capacity ratio of supercapacitor C1 and supercapacitor C2 is 7:6, then according to this ratio, supercapacitor C1 receives 7 / 130V of electricity, and supercapacitor C2 receives 6 / 130V of electricity, and the above-mentioned method can be applied to other supercapacitors; in more embodiments, the allocation of the balanced amount can be randomly performed according to the remaining capacity of supercapacitor C1 and supercapacitor C2, as long as it does not exceed the remaining capacity of each supercapacitor, for example, one supercapacitor can be preferentially selected and another supercapacitor can be used, and the like, and those skilled in the art can select according to specific working conditions, which will not be described here.

[0105] It can be understood that in some other embodiments, each battery cell can also correspond to more supercapacitors, which will not be described here.

[0106] As shown in FIG. 1, each supercapacitor can correspond to one battery cell, supercapacitor C1 is connected in parallel with battery cell E1, supercapacitor C2 is connected in parallel with battery cell E2, supercapacitor C3 is connected in parallel with battery cell E3, supercapacitor C4 is connected in parallel with battery cell E4, supercapacitor C5 is connected in parallel with battery cell E5, supercapacitor C6 is connected in parallel with battery cell E6, supercapacitor C7 is connected in parallel with battery cell E7, and supercapacitor C8 is connected in parallel with battery cell E8. Figure 5

[0107] ​During reverse balancing, the amount to be balanced by each supercapacitor can be evenly distributed to two battery cells connected in series. For example, if the balancing amount of supercapacitor C2 is 0.1V, then battery cells E3 and E4 each receive 0.5V of charge. It is understood that in some other embodiments, the 0.1V can also be proportionally distributed according to the remaining capacity of battery cells E3 and E4. For example, if the current voltage of battery cell E3 is 3.6V (when the maximum capacity is 4.25V, the remaining capacity is 0.65V), and the current voltage of battery cell E4 is 3.7V (when the maximum capacity is 4.25V, the remaining capacity is 0V), then the remaining capacity of battery cell E4 is 0V. If the voltage is 55V, then the remaining capacity ratio of battery cell E3 and battery cell E4 is 65:55. Based on this ratio, the equalization allocation will be as follows: battery cell E3 receives 6.5 / 120V of power, and battery cell E4 receives 5.5 / 120V of power. Similarly, the above method can be applied to other battery cells. In many other implementations, the equalization allocation can be randomly performed based on the remaining capacity of battery cells E3 and E4, as long as it does not exceed the remaining capacity of each battery cell. For example, one battery cell can be selected first, and then another can be used. Those skilled in the art can choose according to the specific operating conditions, which will not be elaborated here.

[0108] It is understandable that in some other implementations, each supercapacitor may correspond to more than one battery cell, which will not be elaborated here.

[0109] Example 3:

[0110] like Figure 6 As shown, Embodiment 3 of the present invention provides a method for balancing the power battery of an electric vehicle. Using the power battery balancing system described in Embodiment 1 of the present invention, the power battery pack is discharged, including the following process:

[0111] Obtain the remaining charge of each individual cell in the power battery pack;

[0112] When the difference between the maximum and minimum remaining charge in each individual battery cell exceeds a set value, discharge equalization is performed until discharge is cut off.

[0113] The discharge equalization includes transferring the excess charge of each individual cell beyond the minimum remaining charge to the corresponding supercapacitor.

[0114] by Figure 2For example, the voltages of the battery cells E1-E13 are 3.5V, 3.5V, 3.6V, 3.7V, 3.5V, 3.4V, 3.5V, 3.5V, 3.6V, 3.7V, 3.5V, 3.4V and 3.4V in turn, the minimum remaining capacity of the battery cells is 3.4V, and the to-be-balanced amounts of the battery cells are 0.1V, 0.1V, 0.2V, 0.3V, 0.1V, 0V, 0.1V, 0.1V, 0.2V, 0.3V, 0.2V, 0V and 0V in turn, and the to-be-balanced amounts are transferred to the corresponding supercapacitors.

[0115] Optionally, in some other embodiments, the balancing control unit acquires the voltage detection values of the supercapacitors in the supercapacitor group, and performs reverse balancing on the battery cells corresponding to the supercapacitors in the supercapacitor group when the remaining capacity of at least one supercapacitor in the supercapacitor group is less than the balancing amount required by the corresponding battery cell. Specifically, for example, when the current voltage of C4 is 1.8V, the balancing amount of battery cell E4 is 0.3V, which exceeds the balancing capacity of C4 (assuming that the maximum voltage of C4 is 2V), at this time, reverse balancing can be performed first, that is, the electric quantity in the supercapacitor is balanced to the battery cell.

[0116] Specifically, the reverse balancing can be:

[0117] transferring the electric quantity greater than the minimum remaining capacity of the supercapacitors in the supercapacitors to the corresponding battery cell;

[0118] stopping the balancing of the supercapacitor group when the remaining capacity of each supercapacitor is equal to the minimum remaining capacity of the supercapacitors or the difference between the remaining capacity of each supercapacitor and the minimum remaining capacity of the supercapacitors is within a preset range;

[0119] continuing the charging process of the power battery group.

[0120] For example, the voltages of C1-C13 are 1.3V, 1.4V, 1.4V, 1.8V, 1.3V, 1.4V, 1.5V, 1.5V, 1.4V, 1.5V, 1.5V, 1.4V and 1.4V in turn, the balancing amounts of C1-C13 are 0V, 0.1V, 0.1V, 0.5V, 0V, 0.1V, 0.2V, 0.2V, 0.1V, 0.2V, 0.2V, 0.1V and 0.1V, and the voltages of the battery cells E1-E13 after balancing are 3.5V, 3.6V, 3.7V, 4.2V, 3.5V, 3.5V, 3.7V, 3.7V, 3.7V, 3.9V, 3.7V, 3.5V and 3.5V in turn.

[0121] The power battery pack is balanced again. At this time, the voltage of C1-C13 is 1.3V, the balance capacity is 0.7V, and the balance values ​​of each battery cell C1-C13 are 0V, 0.1V, 0.2V, 0.7V, 0V, 0V, 0.2V, 0.2V, 0.2V, 0.4V, 0.2V, 0V, and 0V.

[0122] Understandably, in some other implementations, the reverse balancing can also be done in other ways. For example, instead of using the minimum remaining capacity of the supercapacitor as the standard, a set balancing benchmark can be used. With a certain value as the benchmark (this benchmark is less than the minimum remaining capacity of the supercapacitor), all the remaining capacity of each supercapacitor that is greater than this benchmark is transferred to the corresponding battery cell. When the remaining capacity of each supercapacitor is equal to the minimum remaining capacity of the supercapacitor, or when the difference between the remaining capacity of each supercapacitor and the minimum remaining capacity of the supercapacitor is within a preset range, the balancing of the supercapacitor group is stopped, and the charging process of the power battery pack continues.

[0123] Understandably, in some other implementations, the balancing of each supercapacitor within the supercapacitor bank can be performed before or after reverse balancing to ensure that there is always a certain margin to achieve balancing of each individual cell. In other implementations, each supercapacitor can be connected to certain dissipation components to ensure that the supercapacitor can effectively release a certain amount of capacity to achieve balancing of each cell. Those skilled in the art can choose according to the specific operating conditions, which will not be elaborated here.

[0124] like Figure 4 As shown, it is also possible for one battery cell to correspond to two supercapacitors connected in series. Battery cell E1 is connected in parallel with supercapacitors C1 and C2 connected in series; battery cell E2 is connected in parallel with supercapacitors C3 and C4 connected in series; battery cell E3 is connected in parallel with supercapacitors C5 and C6 connected in series; battery cell E4 is connected in parallel with supercapacitors C7 and C8 connected in series; battery cell E5 is connected in parallel with supercapacitors C9 and C10 connected in series; battery cell E6 is connected in parallel with supercapacitors C11 and C12 connected in series; and battery cell E7 is connected in parallel with supercapacitors C13 and C14 connected in series.

[0125] The equalization charge of each battery cell can be evenly distributed across two supercapacitors connected in series. For example, if the equalization charge of battery cell E1 is 0.1V, then supercapacitors C1 and C2 each receive 0.5V of charge. It is understood that in some other embodiments, the 0.1V can also be proportionally distributed based on the remaining capacity of supercapacitors C1 and C2. For example, if the current voltage of supercapacitor C1 is 1.3V (when the maximum capacity is 2V, the remaining capacity is 0.7V), and the current voltage of supercapacitor C2 is 1.4V (when the maximum capacity is 2V, the remaining capacity is 0.6V), then the supercapacitor... The remaining capacitance ratio of capacitor C1 and supercapacitor C2 is 7:6. Based on this ratio, the equalization amount is allocated, with supercapacitor C1 receiving 7 / 130V and supercapacitor C2 receiving 6 / 130V. Similarly, the above method can be applied to other supercapacitors. In many other embodiments, the equalization amount can be randomly allocated based on the remaining capacitance of supercapacitors C1 and C2, as long as it does not exceed the remaining capacitance of each supercapacitor. For example, one supercapacitor can be selected first, and then the other can be used. Those skilled in the art can choose according to specific operating conditions, which will not be elaborated here.

[0126] It is understandable that in some other implementations, each battery cell may correspond to more supercapacitors, which will not be elaborated here.

[0127] like Figure 5 As shown, it can also be that one supercapacitor corresponds to two battery cells. Supercapacitor C1 is connected in parallel with battery cells E1 and E2 connected in series; supercapacitor C2 is connected in parallel with battery cells E3 and E4 connected in series; supercapacitor C3 is connected in parallel with battery cells E5 and E6 connected in series; supercapacitor C4 is connected in parallel with battery cells E7 and E8 connected in series; supercapacitor C5 is connected in parallel with battery cells E9 and E10 connected in series; supercapacitor C6 is connected in parallel with battery cells E11 and E12 connected in series; and supercapacitor C7 is connected in parallel with battery cells E13 and E14 connected in series.

[0128] During reverse balancing, the amount to be balanced by each supercapacitor can be evenly distributed to two battery cells connected in series. For example, if the balancing amount of supercapacitor C2 is 0.1V, then battery cells E3 and E4 each receive 0.5V of charge. It is understood that in some other embodiments, the 0.1V can also be proportionally distributed according to the remaining capacity of battery cells E3 and E4. For example, if the current voltage of battery cell E3 is 3.6V (when the maximum capacity is 4.25V, the remaining capacity is 0.65V), and the current voltage of battery cell E4 is 3.7V (when the maximum capacity is 4.25V, the remaining capacity is 0V), then the remaining capacity of battery cell E4 is 0V. If the voltage is 55V, then the remaining capacity ratio of battery cell E3 and battery cell E4 is 65:55. Based on this ratio, the equalization allocation will be as follows: battery cell E3 receives 6.5 / 120V of power, and battery cell E4 receives 5.5 / 120V of power. Similarly, the above method can be applied to other battery cells. In many other implementations, the equalization allocation can be randomly performed based on the remaining capacity of battery cells E3 and E4, as long as it does not exceed the remaining capacity of each battery cell. For example, one battery cell can be selected first, and then another can be used. Those skilled in the art can choose according to the specific operating conditions, which will not be elaborated here.

[0129] It is understandable that in some other implementations, each supercapacitor may correspond to more than one battery cell, which will not be elaborated here.

[0130] Example 4:

[0131] like Figure 7 As shown, Embodiment 4 of the present invention provides a method for balancing the power battery of an electric vehicle, utilizing the power battery balancing system of the electric vehicle described in Embodiment 1 of the present invention, including the following process:

[0132] (1) Battery discharge equalization:

[0133] During the discharge process, control switches S0-S15 transfer power to the supercapacitor through one or more combined transformers to achieve discharge balance of the lithium-ion battery pack.

[0134] When the SOC is greater than a certain value, there is no discharge circuit cutoff fault in the BMS, and Vmin is greater than a certain value, the voltage difference is greater than a certain value, the SOC of the battery pack minus the SOC of the supercapacitor pack is greater than 10%, and there is no voltage acquisition fault, calculate the average voltage of all individual cells, mark the 10 cells with the highest average voltage of individual cells, and transfer the power to the lowest individual cell of the supercapacitor pack until the voltage is greater than the average individual cell voltage of the supercapacitor pack.

[0135] (2) Battery charging equalization;

[0136] The control switch S0-S15 transfers the electric quantity to the super capacitor through single or multiple combination transformers to realize the discharge equalization of the lithium ion battery pack during the charging process.

[0137] When the SOC is less than a certain value, the BMS has no discharge circuit cut-off failure, Vmax is less than a certain value, the pressure difference is greater than a certain value, the battery pack SOC-super capacitor group SOC is greater than 10%, and there is no voltage acquisition failure, the average voltage of all single cells is calculated, the highest 10 strings of cells greater than the average voltage of the single cells are marked, and the electric quantity is transferred to the lowest single cell capacitor of the super capacitor to the voltage greater than the average single cell capacitor voltage of the super capacitor group.

[0138] (3) Mute equalization

[0139] After the BMS sleeps for a certain time (the battery or super capacitor is fully at rest), the clock control switch S0-S15 transfers the electric quantity to the single cell through single or multiple combination transformers to realize the charging equalization of the lithium ion battery pack.

[0140] When the SOC is greater than a certain value, Vmax is less than a certain value, the pressure difference is greater than a certain value, the super capacitor group SOC-battery pack SOC is greater than 10%, there is no voltage acquisition failure, and the BMS supply voltage is greater than 10V, the average voltage of all single cells is calculated, the highest 10 strings of super capacitors greater than the average voltage of the single cells are marked, and the electric quantity is transferred to the lowest single cell battery of the battery pack to the voltage greater than the average single cell battery voltage of the battery pack.

[0141] Example 5:

[0142] The embodiment 5 of the present application provides an electric vehicle, which comprises the electric vehicle power battery equalization system of the embodiment 1 of the present application, and the power battery group and the super capacitor group are directly or indirectly connected with the motor drive control system of the electric vehicle.

[0143] For example, optionally, the power battery group can be directly connected with the motor drive control system of the electric vehicle, and the super capacitor group is connected with the motor drive control system of the electric vehicle through a voltage regulator, and the voltage regulator can adopt an existing voltage regulator design scheme (for example, Chinese patent CN03134523.9, electric vehicle super capacitor auxiliary power system), which will not be described here.

[0144] Example 6:

[0145] The embodiment 6 of the present application provides an electric vehicle, which utilizes the electric vehicle power battery equalization method of the embodiment 2 or the embodiment 3 or the embodiment 4 of the present application.

[0146] Those skilled in the art will appreciate that embodiments of the application can be readily used as software, hardware, or a combination of software and hardware. In a software embodiment, the methods can be tangibly embodied in a machine-readable storage medium having stored thereon instructions that can be used to program a processing system to perform the methods. The term "processor," as used herein can refer to one or more processors capable of executing a software routine created to perform one or more processes described herein. The processor can be implemented as one or more central processing units (CPUs), one or more microprocessors, one or more microcomputers, one or more microcontrollers, one or more digital signal processors, one or more graphics processing units (GPUs), one or more processing cores, one or more processing units, one or more processing circuits, one or more processing devices, one or more processors, one or more processing means, or any combination thereof. The processor can be configured to execute instructions stored in a memory or other type of storage device to perform processes described herein.

[0147] The present application is described in reference to the drawings, which are as follows: Figure 1 Figure 1

[0148] Figure 1 Figure 1

[0149] Figure 1 Figure 1

[0150] Those skilled in the art will appreciate that implementing all or part of the methods described above can be done through a computer program that instructs relevant hardware. The program can be stored in a computer-readable storage medium, and when executed, can include the processes described above. The storage medium can be a disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), or the like.​​​​​​​​

[0151] The above descriptions are only the preferred embodiments of the present application, not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. A method for balancing electric vehicle power battery, characterized in that: a power battery pack is charged by using an electric vehicle power battery balancing system, and the method comprises the following processes: if the charging cut-off condition is met, the charging is stopped; otherwise, the following processes are performed: obtaining the residual capacity of each single battery in the power battery pack; transferring the capacity of each single battery greater than the minimum residual capacity to the corresponding super capacitor; when the residual capacity of each single battery is equal to the minimum residual capacity, or the difference between the residual capacity of each single battery and the minimum residual capacity is within a preset range, the balancing is stopped, and the charging of each single battery is started, and the above processes are repeated until the charging of the power battery pack is completed; after the charging of the power battery pack is completed, each super capacitor of the super capacitor pack is charged according to the design redundancy until the charging is completed; reverse balancing, comprising: transferring the capacity of each super capacitor greater than the minimum residual capacity of the super capacitor to the corresponding single battery; when the residual capacity of each super capacitor is equal to the minimum residual capacity of the super capacitor, or the difference between the residual capacity of each super capacitor and the minimum residual capacity of the super capacitor is within a preset range, the balancing of the super capacitor pack is stopped; the charging process of the power battery pack is continued; the system comprises: a power battery pack, a super capacitor pack, a balancing control unit and a balancing control circuit; each super capacitor in the super capacitor pack is connected in series, and each single battery in the power battery pack is connected in parallel with the corresponding super capacitor through the balancing control circuit; the balancing control unit communicates with the power battery pack, the super capacitor pack and the balancing control circuit respectively; the balancing control unit is configured to receive the residual capacity of each single battery and the voltage detection value of each super capacitor, and send a balancing control instruction to the balancing circuit; the charging redundancy of the super capacitor is greater than or equal to the maximum balancing amount of each single battery. 2.The method for balancing electric vehicle power battery according to claim 1, characterized in that: the charging cut-off condition at least includes: reaching the highest charging voltage of the single battery, reaching the longest charging time of the single battery. 3.The method for balancing electric vehicle power battery according to claim 1, characterized in that: obtaining the voltage detection value of each super capacitor in the super capacitor pack, and when the residual capacity of at least one super capacitor in the super capacitor pack is less than the balancing amount demand of the corresponding single battery, performing reverse balancing of each super capacitor in the super capacitor pack to the corresponding single battery. 4.The method for balancing electric vehicle power battery according to claim 1, characterized in that: the charging of the power battery pack comprises the following processes: when the SOC is greater than a set value, the BMS has no discharge loop cut-off fault, the minimum single battery voltage is greater than a set value, the voltage difference of each single battery is greater than a set value, the difference between the SOC of the battery pack and the SOC of the super capacitor pack is greater than a set value, and there is no voltage collection fault; calculating the average voltage of all single batteries, transferring the capacity of the highest N single batteries greater than the average voltage of the single batteries to the single capacitor with the lowest voltage, until the voltage of the single capacitor is greater than the average single capacitor voltage of the super capacitor pack.

5. The electric vehicle power battery equalization method of claim 1, wherein: discharging the power battery pack comprises the following process: obtaining the residual capacity of each single battery in the power battery pack; when the difference between the maximum residual capacity and the minimum residual capacity in each single battery is greater than a set value, discharging equalization is performed until the discharging cutoff; the discharging equalization comprises: transferring the capacity greater than the minimum residual capacity of each single battery to the corresponding super capacitor; reverse equalization comprises: transferring the capacity greater than the minimum residual capacity of each super capacitor to the corresponding single battery; when the residual capacity of each super capacitor is equal to the minimum residual capacity of the super capacitor, or the difference between the residual capacity of each super capacitor and the minimum residual capacity of the super capacitor is within a preset range, the equalization of the super capacitor group is stopped; the discharging process of the power battery pack is continued.

6. The electric vehicle power battery equalization method of claim 5, wherein: obtaining the voltage detection value of each super capacitor in the super capacitor group, when the residual capacity of at least one super capacitor in the super capacitor group is less than the equalization amount required by the corresponding single battery, reverse equalization is performed on each super capacitor in the super capacitor group to the corresponding single battery.

7. The electric vehicle power battery equalization method of claim 1, wherein: charging the power battery pack comprises the following process: when the SOC is less than a set value, there is no discharging loop cut-off fault in the BMS, the maximum voltage of the battery single is less than a set value, the voltage difference of each battery single is greater than a set value, the difference between the SOC of the battery group and the SOC of the super capacitor group is greater than a set value, and there is no voltage collection fault; calculating the average voltage of all single batteries, transferring the capacity of the highest N battery single greater than the average voltage of single battery to the single capacitor with the lowest voltage, until the voltage of the single capacitor is greater than the average single capacitor voltage of the super capacitor group.

8. The electric vehicle power battery equalization method of claim 1, wherein: charging the power battery pack comprises the following process: after the BMS sleeps for a set time, when the SOC is greater than a set value, the maximum battery single voltage is less than a set value, the voltage difference of each single battery is greater than a certain value, the difference between the SOC of the super capacitor group and the SOC of the battery group is greater than a set value, there is no voltage collection fault, and the BMS supply voltage is greater than a set value; calculating the average voltage of all single batteries, transferring the capacity of the highest N battery single greater than the average voltage of single battery to the single capacitor with the lowest voltage, until the voltage of the single capacitor is greater than the average single capacitor voltage of the super capacitor group.

9. An electric vehicle adopting the electric vehicle power battery equalization method of any one of claims 2-8, wherein: the power battery group and the super capacitor group are directly or indirectly connected with the motor drive control system of the electric vehicle. ​

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